Exhaust Gas Recirculation (“EGR”) is an important element for both diesel and gasoline engines, particularly engines utilizing charge air boosting or compression (ex. exhaust driven turbocharger or engine driven supercharger,) for both fuel consumption improvements and for the reduction of regulated tailpipe exhaust gas emissions.
In engines utilizing an exhaust driven turbocharger or engine driven supercharger, high pressure EGR may be diverted from a location upstream of the turbocharger and is supplied to the compressed intake charge during high load operation. However, during high load operation of the internal combustion engine, the pressure differential (“ΔP”) between the EGR supply and the compressed intake charge may be negative. Specifically, the supply pressure of the EGR may drop below that of the compressed intake charge making it difficult, if not impossible, to supply EGR to the intake system (PINTAKE>PEGR).
It has been proposed to utilize a venturi system in the intake system to decrease the intake pressure to allow for the ΔP between the EGR supply and the compressed intake charge to be momentarily positive allowing for the delivery of EGR to the intake system under high load operation. In such an instance, including operation of the engine at other than high loads, an even delivery and distribution of the EGR is desirable.